This is our largest available container of CRL Hot Melt Butyl. This 55 gallon drum, which contains approximately 436 pounds of material (net), is for use with 55 gallon dispensing systems. This is a 100% solids, hot applied butyl-based sealant designed to give tenacious adhesion to glass and aluminum for a moisture proof seal in insulating glass units. CRL 520 Butyl is a one-component sealant system with lower moisture vapor transmission rates than most polysulfide, silicone or polyurethane systems. It features low residual tack and excellent corner knitting. This is the same formulation used with all CRL Hot Melt Systems.